Each block is steel and hardened to 65RC, stress relieved, lapped to accurate size, parallelism & flatness, then carefully inspected and marked for size designed to meet close tolerance.
Each set includes standard sizes found in more expensive sets. Each block individually serialized and conforms to the rigid standards of the National Bureau Of Standards.
Grade AS-2 (B) tolerance = ±.000050".
Grade 0 (2) tolerances = 4, -2 millionths.
Grade AS-1 (3) tolerances = +8, -4 millionths.
Product # 100-811, CGB-200 and CGB-300 comes with NIST Certificate.
WARNING: This Product Can Expose You To Materials And/Or Chemicals Which Are Known To The State Of California To Cause Cancer And/Or Reproductive Harm.
